D600 vs. D800... which one is the most balanced camera?

IQ-wise they bare almost the same DR, the same noise performance for equal size prints, ...even the same visible resolution for the same prints... D600 is faster and cheaper, D800 is better build and with more functions... So which one is more balanced?

You could go both ways. I'm sure I could pick up either camera and do pretty much any task. I can cover a basketball game at 4 fps and get plenty of good shots (I'd miss some too, but who covers every play anyways?) I can make huge prints with 24 MP files (a billboard sized print from a 24 MP file might not be as sharp up close as one made from a 36 MP file, but who shoves their nose up to large prints anyways?) So...here's the politically correct answer: both are balanced cameras, and both can confidently handle any task.

But if you want my personal opinion on which is more balanced, I'd go with the D600. 24 MP is already a ton of resolution - enough to make large prints, and enough to retain usable files after heavy cropping. The D600's quieter shutter makes it more usable in quiet settings. It also shoots faster, and flushes the smaller files to the card faster. If I didn't know what opportunities would come up, I'd rather have a D600, because the higher framerate would be more likely to catch action (I don't like handling action with anything slower than 5 fps. 5.5 fps is barely fast enough), and the quieter shutter would make me less hesitant to shoot. The D800 seems more like a specialized camera for people who need as much resolution as they can get, at the expense of some other things (like speed).

Another note: the weight/size difference is immaterial. Once you pick up a DSLR, you're not going for light weight or size. Even a tiny DSLR like the Sony a230 is a handful to carry around. And if you're using high end FF glass, most of the weight comes from the lens anyways. The price difference also means little. Someone willing to go over $2000 would likely be willing to put in a few hundred extra dollars to get something that better fits his/her needs. If the D800 was a 18 or 16 MP camera that could shoot 8 fps, I'd have bought that instead of the D600.